I. Field of the Invention
A critical processing step in many genetic engineering and molecular biology techniques is the selection of a particular cell or cell colony from a multitude of similar species. Hybridoma technology, where the fusion and plating of hybrid cells generally results in several thousand clones is one example of a process requiring such selection. The clones are typically screened by immunoassay techniques to select the single clone producing the specific antibody of interest. To preserve the activity of the cells, the screening must take place within a few days. Screening is generally accomplished by the use of a series of microplates, each containing a large number of wells, each well designed to accommodate a single clone.
Screening techniques involving microplates generally involve two or more steps in each of which a reagent or reagent mixture is added to each well. For reliability and accuracy of results, the wells must be emptied between these steps, and rinsed with a washing solution to eliminate non-specifically bound reagents. It is often necessary to rinse and evacuate each of the wells in a large number of microplates several times within the course of a single screening procedure.
The present invention relates to an apparatus for the washing of all wells in a microplate at once, in a highly efficient and reliable manner.
II. Description of the Prior Art
A variety of microplate washers are commercially available. A manual device known as the "Miniwash Washer-Aspirator" is available from Dynatech Laboratories, Inc., Arlington, Virginia. This device is hand-operated, and capable of filling and evacuating only one row (eight wells) of a microplate at one time. A thorough wash of an entire microplate takes several minutes, and the likelihood of spillage from one well to an adjacent well is a serious disadvantage. A further manually-operated device is the "Dynawasher II", also available from Dynatech Laboratories, Inc. Although this device is designed to handle all wells in a microplate simultaneously, it has two positions, located at the extreme ends of a horizontal track, one for aspiration and the other for filling the wells with wash fluid. Finally, an automatic device bearing the name "Titertek.RTM. Multi-Wash" is available from Flow Laboratories, Inc., McLean, Virginia. This device is capable of washing and filling only two rows of a microplate at a time. The mechanism is completely enclosed, precluding detection by the operator of such problems as incomplete filling or aspiration of the wells, both of which are known to plague this instrument.